In many surgical procedures, it is desirable to provide one or more working channels into a body cavity through which various instruments can be passed to view, engage, and/or treat tissue to achieve a diagnostic or therapeutic effect. In laparoscopic abdominal procedures for example, the abdominal cavity is generally insufflated with CO2 gas to a pressure of around 15 mm Hg. The abdominal wall is pierced and one or more tubular cannulas, each defining a working channel, are inserted into the abdominal cavity. A laparoscopic telescope connected to an operating room monitor can be used to visualize the operative field and can be placed through one of the working channels. Other laparoscopic instruments such as graspers, dissectors, scissors, retractors, etc. can also be placed through one or more of the working channels to facilitate various manipulations by the surgeon and/or surgical assistant(s).
One problem with existing methods and devices is that these tubular cannulas limit the degree to which devices passed through the cannula can be angulated with respect to the operative field. This can undesirably prolong and complicate the surgery, and in same cases can require placement of additional access devices and formation of additional incisions associated therewith.
Another drawback to existing access devices is that they can suffer from poor retention and sealing capabilities. For example, angulation of various surgical tools inserted through traditional cannulas can compromise the seal between the cannula and the tissue wall, undesirably allowing insufflation gas to escape. In addition, the cannula can have a tendency to “back out” or slide proximally out of the incision.
Accordingly, there is a need for surgical access methods and devices that provide improved sealing, retention, and maneuverability characteristics.